Copper Crystal Twins

Macle Twins

Copper frequently twins by reflection and composition on {111} planes. The resulting twins may look different depending on the external forms present on the copper crystals.

The visible "reentrant angles" on the above idealized crystal draing are areas of more rapid crystal growth. As a result, such twins are frequently distoreted compared to untwinned crystals with the same external crystal forms.

Bearpaw twins